1. Field of the Invention
The present invention generally relates to an atmosphere sampler and, more particularly, to a sampler of gas-borne particles.
2. Description of the Prior Art
There are many applications in which it is desirable to sample small particles, contained in a gas, e.g., the atmosphere (air). This is generally performed by causing the air to pass through a filter which is designed to permit the air to pass therethrough while trapping the particles for subsequent analysis. One example of a prior art sampler of air-borne particles is described in U.S. Pat. No. 3,795,135. In said patent a filter arrangement is disclosed consisting of a plurality of filter discs with holes of different dimensions. These different filter discs are designed to trap particles of different dimensions. The need for a plurality of discs clearly increases the filter's complexity and cost.